Yes i found this flowchart a month ago and it looks quite understandable. Also for me was usefull Setup guide for IracingUnfortunatelly with all of this materials im still not able to do the good setup from scratch. Finally i have always stayed in trial and error method.

I have problem too, after a many and many laps i find good setup for Q session (mainly now in F1 1991) but than for the race i am much slower than other driver in comparsion to Q standings and lap times, especialy at race start with full tank and cold tyres I am strugling too much and often lost some positions.